1. Technical Field
The present invention relates to an image printing apparatus on which an ink cartridge is detachably mountable.
2. Related Art
Both now and in the past, in a so-called tube supply type image printing apparatus, an ink cartridge is disposed on the outside of a carriage having a printhead mounted thereon, and the ink cartridge and the printhead are connected to each other via a tube. The ink cartridge is horizontally mounted on, for example, a cartridge mounting unit having an opening at the front side of a body via the opening. The cartridge mounting unit accommodates the ink cartridge so as to be attachable thereto and detachable therefrom. When the ink cartridge is mounted on the cartridge mounting unit, an ink passage is formed from the ink cartridge to the printhead. Ink is supplied from the ink cartridge to the printhead via the ink passage.
A remaining amount detecting unit is provided so as to detect the remaining amount of ink inside the ink cartridge, and the cartridge mounting unit is provided with a sensor that is used to detect the remaining amount detecting unit of the ink cartridge.
In order to manage the remaining amount of ink inside the ink cartridge, the known image printing apparatus counts ink droplets ejected from the printhead by using a dot counter. The dot count value is reset when the ink cartridge is exchanged. Whether the ink cartridge is exchanged is determined on the basis of the user's input. In the known image printing apparatus, the dot count value is temporarily saved before being reset in consideration of the user's erroneous input. When it is determined that an erroneous input is performed by the user, the saved dot count value may be set again executed by a user's correction input.
However, when the user recognizes the erroneous input at the time of the exchange of the ink cartridge, the dot count value may be set again by receiving a user's correction input. However, when the user does not recognize the erroneous input, the dot count value can not be set again. For example, in an image printing apparatus used by plural users, a user may input some information after exchanging the ink cartridge. In this case, since other users may not recognize the erroneous input even if the former user inputs wrong information, an image printing operation is performed without setting the dot count value again, and hence there is a concern in that a so-called void ejection may occur in which the printhead is operated without ink.
The image printing apparatus may include a unit that detects the exchange of the ink cartridge. However, when the ink cartridge is exchanged while power of the image printing apparatus is turned off, there is a problem in that the unit may not be able to detect the exchange of the ink cartridge. On the contrary, an image printing apparatus is known which determines the exchange of the ink cartridge on the basis of the result of comparison between the detection result of the remaining amount of ink before turning off power and the detection result of the remaining amount of ink upon turning on power.
However, since the exchange of the ink cartridge is determined on the basis of the detection result of the remaining amount of ink immediately after turning on power, there is a concern in that an erroneous determination may be performed when the currently used ink cartridge is inserted or extracted without mounting a new ink cartridge. More specifically, when the ink cartridge is extracted and inserted, there is a concern in that ink is adhered to the remaining amount detecting unit or bubbles are generated in the ink level when the ink level inside the ink cartridge is shaken. When the remaining amount of ink is detected before the ink adhered to the remaining amount detecting unit flows to be dropped therefrom or the bubbles are removed, there is a concern in that an erroneous determination may be performed such that ink remains in the ink cartridge due to the adhered ink or the bubbles even when the remaining amount of ink is small. When an image printing operation is performed after it is determined that the ink cartridge is exchanged on the basis of the erroneous detection result, there is a concern that void ejection of ink may occur as described above.